The zones found by this method are added to the Zones collection of this page. Any previously added zones will be removed from Zones first.

This method finds the zone coordinates (OcrZone.Bounds which will always have units of pixels and type (OcrZone.ZoneType). The type of the zone determines its role in the page layout and can be classified into three different groups:

The OcrZoneType.Table type. A zone having this type means that the zone is detected as containing a table, i.e. with columns, with or without a grid. Such zones will be handled differently from those of flowed text type zones.

The OcrZoneType.Graphic type means a zone contains graphics, i.e. this zone will not be recognized at all. The only reason to have such a zone is to save or export the image inside the zone area.

Note: If this IOcrPage is an empty page, in other words, when the OCR engine performs automatic page decomposing with the AutoZone method and could not find any zones in it, the Recognize method will fail with an exception. It is recommended you call AutoZone and then check if there is at least one zone found by the engine (using Zones.Count). If the count is zero, do not call Recognize.

If a recognition module is not able to recognize an object (i.e. character, or checkmark etc.), this object will be marked as a rejected one. It will become marked by a rejection symbol during conversion to the final output document. Note that IOcrDocumentManager.RejectionSymbol can be set to specify the rejection symbol used in the final document.

Note on AutoZone/Recognize and the page image: In certain cases, AutoZone and Recognize will perform image processing on the page that might result in the page being manipulated. For example, if you add a zone of type table, the engine might automatically deskew the page if required. This result in the image representation of the image to be different after AutoZone or Recognize is called. If your application has a requirement to view the image of the page, then call GetRasterImage after AutoZone or Recognize to get the latest version of the image representation of the page in case it has changed. The LEADTOOLS Main OCR C# and VB demos do exactly that.

Example

This example will perform auto-zoning on an OCR page then displays information about the zones found.